how to calculate pump speed for solar panels

[joedoe]

hi TFP,

I have read posts re: this type of question but admittedly have struggled with figuring out how to calculate all the variables to figure out what speed to set the pump on for use of solar panels.

I recently installed 5 4x12 aquasol solar panels on SW facing 8/12 pitch garage roof approximately 25feet at peak of roof, 12 feet to inlet and the return from the panels is approx. 40 feet back to equipment area from outlet at peak of roof. I have 2" piping throughout the entire pool system. I have 3 returns which are linked with piping around entire pool with uprights to each return, length approx35 to pool area then 100feet around pool,(hope that makes sense). I also have a separate line to the cozy cove, length is approx. 60feet from pump.

thanks

 

[JVTrain]

This thread has some very good discussion on this topic: Solar panels with variable speed pump??

 

[joedoe]

thanks for the response JV train. it appears the solar kicked on today, but the RPM were at 750, which didn't appear to be pushing enough to get a good flow, i.e. no significant flow from returns, I upped the speed to 2200 RPM and it seems to work well, lots of bubbles and heat for a few minutes then just slightly warmer than pool, which I understand is what you want.

thanks

 

[mas985]

Your running filter pressure should be several PSI higher than the height of the panels above the pressure gauge divided by 2.31. So if you have a 25' high panel installation, filter pressure should be at least 14 PSI assuming all the water from the pump is going to the panels.